Seems like a simple enough requirement, but I'm struggling:

1. I want to add an option field to the "Add New Site".
   A simple text option is fine. How do I do this?

2. I need to save this custom blog option when the site is created.

I know I can use the 'wpmu_new_blog' hook, which passes the $meta variable with supplied options, but I'm wondering if there's a way to do this all in one step so I don't have to perform another DB query, or worse yet, override/replace the whole site creation process?

Notes:

I'm using WP 3.3.1 with a MultiSite setup. I'm writing a plugin that lists all the Sites which match the specified custom field value (let's call it "type").

Also, I'm an experienced PHP developer but I'm still relatively new to WordPress hacking, so please assume I am not yet intimately familiar with all of the various WP functions and hooks.